﻿namespace USSDRunner
{
    using System;
    using System.Diagnostics;
    using System.Windows;
    using System.Windows.Navigation;

    using Microsoft.Phone.Controls;
    using Microsoft.Phone.Shell;

    using USSDRunner.ViewModels;

    /// <summary>
    /// Represents USSD Runner application.
    /// </summary>
    public partial class App
    {
        private static MessageViewModel viewModel;

        // Avoid double-initialization
        private bool isApplicationInitialized;

        /// <summary>
        /// Initializes a new instance of the <see cref="App"/> class.
        /// </summary>
        public App()
        {
            // Global handler for uncaught exceptions. 
            UnhandledException += HandleApplicationUnhandledException;

            // Standard Silverlight initialization
            InitializeComponent();

            // Phone-specific initialization
            InitializePhoneApplication();

            // Show graphics profiling information while debugging.
            if (Debugger.IsAttached)
            {
                // Display the current frame rate counters.
                Current.Host.Settings.EnableFrameRateCounter = true;

                // Show the areas of the app that are being redrawn in each frame.
                // Application.Current.Host.Settings.EnableRedrawRegions = true;

                // Enable non-production analysis visualization mode, 
                // which shows areas of a page that are handed off GPU with a colored overlay.
                // Application.Current.Host.Settings.EnableCacheVisualization = true;

                // Disable the application idle detection by setting the UserIdleDetectionMode property of the
                // application's PhoneApplicationService object to Disabled.
                // Caution:- Use this under debug mode only. Application that disables user idle detection will continue to run
                // and consume battery power when the user is not using the phone.
                // PhoneApplicationService.Current.UserIdleDetectionMode = IdleDetectionMode.Disabled;
            }
        }

        /// <summary>
        /// Gets a static ViewModel used by the views to bind against.
        /// </summary>
        /// <returns>The MessageViewModel object.</returns>
        public static MessageViewModel ViewModel
        {
            get
            {
                return viewModel;
            }

            set
            {
                viewModel = value;
            }
        }

        /// <summary>
        /// Gets the root frame of the Phone Application.
        /// </summary>
        /// <returns>The root frame of the Phone Application.</returns>
        public PhoneApplicationFrame RootFrame { get; private set; }

        // Code to execute if a navigation fails
        private static void HandleRootFrameNavigationFailed(object sender, NavigationFailedEventArgs e)
        {
            if (Debugger.IsAttached)
            {
                // A navigation has failed; break into the debugger
                Debugger.Break();
            }
        }

        // Code to execute on Unhandled Exceptions
        private void HandleApplicationUnhandledException(object sender, ApplicationUnhandledExceptionEventArgs e)
        {
            if (Debugger.IsAttached)
            {
                // An unhandled exception has occurred; break in the debugger
                Debugger.Break();
            }

            // ToDo: investigate error handling.
            e.Handled = true;
            ErrorPage.Exception = e.ExceptionObject;
            ((PhoneApplicationFrame)RootVisual).Source = new Uri("/ErrorPage.xaml", UriKind.Relative);
        }

        // Code to execute when the application is launching (e.g., from Start)
        // This code will not execute when the application is reactivated
        private void HandleApplicationLaunching(object sender, LaunchingEventArgs e)
        {
            ViewModel = new MessageViewModel();
            ViewModel.Initialize();
        }

        // Code to execute when the application is activated (brought to foreground)
        // This code will not execute when the application is first launched
        private void HandleApplicationActivated(object sender, ActivatedEventArgs e)
        {
            if (ViewModel != null && ViewModel.IsDataLoaded)
            {
                return;
            }

            if (viewModel == null)
            {
                ViewModel = new MessageViewModel();
            }

            ViewModel.LoadData();
        }

        // Code to execute when the application is deactivated (sent to background)
        // This code will not execute when the application is closing
        private void HandleApplicationDeactivated(object sender, DeactivatedEventArgs e)
        {
            // Ensure that required application state is persisted here.
        }

        // Code to execute when the application is closing (eg, user hit Back)
        // This code will not execute when the application is deactivated
        private void HandleApplicationClosing(object sender, ClosingEventArgs e)
        {
        }

        #region Phone application initialization

        // Do not add any additional code to this method
        private void InitializePhoneApplication()
        {
            if (this.isApplicationInitialized)
            {
                return;
            }

            // Create the frame but don't set it as RootVisual yet; this allows the splash
            // screen to remain active until the application is ready to render.
            RootFrame = new PhoneApplicationFrame();
            RootFrame.Navigated += CompleteInitializePhoneApplication;

            // Handle navigation failures
            RootFrame.NavigationFailed += HandleRootFrameNavigationFailed;

            // Ensure we don't initialize again
            this.isApplicationInitialized = true;
        }

        // Do not add any additional code to this method
        private void CompleteInitializePhoneApplication(object sender, NavigationEventArgs e)
        {
            // Set the root visual to allow the application to render
            if (RootVisual != RootFrame)
            {
                RootVisual = RootFrame;
            }

            // Remove this handler since it is no longer needed
            RootFrame.Navigated -= CompleteInitializePhoneApplication;
        }

        #endregion
    }
}